Previously, many types of orthodontic appliances have been used in endeavoring to provide an effective means for producing straight teeth in a persons mouth. In the past, removable appliances have employed a resilient arch wire around the labial side of the teeth and another contiguous with the teeth on the lingual side. The above wires are permanently attached to a clasp, or the like, that are secured to the midregion teeth on each side. Further, an expansion plate or wire is disposed across the roof of the mouth and by physically adjusting each wire, a force is placed upon the teeth in such a manner as to reposition individual teeth into the desired position.
Feb. 6, 1987 Harry W. Tepper filed an application for a removable orthodontic appliance which was abandoned in favor of a continuation-in-part application issuing a U.S. Pat. No. 4,976,614. The instant application is an improvement of this patented device by the same inventor with the improvement consisting of the use of a compressible tension bridge positioned within a wearers palatal arch replacing the transverse wire arch structure that presently has a sinuous configuration both of which utilize the so-called shape memory metal. The unique physical and temperature responsive characteristics of this metal is that when the temperature is above a specific transitional range it has the propensity to return to its original shape. Below this range the metal is in a martensitic state which is pliable and easily formed. Above the transitional range the metal reverts to an austenitic state gaining strength seeking to return to its original configuration. This type of shape memory alloy was earlier disclosed in its basic form in the following U.S. Patents:
______________________________________ U.S. Pat. No. Inventor Issue Date ______________________________________ 3,174,851 Buehler et al Mar. 23, 1965 3,351,463 Rozner et al Nov. 7, 1967 ______________________________________
The application of this metal, particularly in the use of a radially compressible bridge, has not been employed by prior art relative to the improvements in the instant invention, however, the following U.S. Patents are considered related:
______________________________________ U.S. Pat. No. Inventor Issue Date ______________________________________ 4,976,614 Tepper Dec. 11, 1990 4,468,196 Keller Aug. 28, 1984 4,433,956 Witzig Feb. 28, 1984 4,424,031 Dahan Jan. 3, 1984 ______________________________________
U.S. Pat. No. 4,976,614 issued to the present inventor discloses a removable orthodontic appliance upon which the instant improvement is based. The improvement utilizes a pair of arch wires on the labial and lingual side of the front teeth with a pair of clasps attached to the midregion teeth, as previously taught. A pair of structural braces and a radially compressible tension bridge are added, both being new and not considered in the inventors previous patent, making a new and novel combination.
Keller in U.S. Pat. No. 4,468,196 employs a single arch wire attached to a selected molar on each side of the jaw. The arch wire is covered by a hardenable material in which an optional buccal wire is provided on the outer surface of the front teeth.
Witzig, in Pat. No. 4,433,956, corrects class II malocclusions using acrylic anterior segments over the front teeth and an expandable screw connected to a similar posterior segment over the mid-range teeth. The appliance is mechanically expanded in stages to maximize the utilization of corrective lower jaw movements which result from the anchoring of the device in the upper mouth.
Pat. No. 4,424,031 of Dahan anchors his appliance on opposed molars with a fluted tube-like element. Force conveying means enter each element through a lengthwise groove and is locked in place. This element consists of a facial arc and moves a radial direction relative to the tube-like element forcing the anchored teeth radially.